The Breeze is nice. Night Elf Men in general seem to not wear shirts. Good thing all of them are stupid hot. Could you imagine a Fat Night Elf Male? It could also be that trick where you train your whole fighting style around the enemy trying to stab you in the chest because its armorless.

I believe I once heard that the lore reason was to be as unburdened as possible for the sake of mobility; which by the way I think is rather stupid for several reasons. Really, how heavy is bloody shirt?

Of course I'd imagine the real reason is rule of cool. Can't show off those tattoos if they're hidden under a cuirass.

But then their pants don't burn off... Clearly it because turning into a demon would rip any shirt you were wearing like the hulk... "But Druids shapeshift too!!" Well now maybe it's a night elf cultural thing and a demon thing!! Nane how many demons wear full shirts that cover their chest???

Lore-wise, Demon Hunters have superb blademanship and athletic ability, which in game basically equates to incredible parrying and dodging skills. And from what we've seen with warlocks, I could imagine that there are tricks with fel magic that can give them some strong regenerative powers.

None of this makes them invincible of course, but if something does kill them, it won't just be because they forgot to wear a coat.

I could be wrong but their tattoos might also be imbued with Fel. I don't know though. It's just weird how they glow in some art.

In terms of style though, a demon hunter is a hit-and-run specialist. From the artists perspective(which is Samwise, in this case), they wanted to showcase a character that was not by any means a tank.

Also, Demon Hunters take things to an extreme. Even a monk might wear a uniform or robe or something, but the idea that armor slows you down means demon hunters -- who would essentially be Warcraft's equivalent to steroid abusers -- use this logic to just not wear any clothes they don't have to.

Just like how demon hunters also specialize in a spell that basically looks like they're setting themselves on fire. They're extreme, and will do whatever it takes to win.